STM-D-0982Paper2014Published and peer-reviewed

Design of magnetized liner inertial fusion experiments using the Z facility

Adam B. Sefkow · Stephen A. Slutz · Joseph M. Koning · Michael M. Marinak · Kyle J. Peterson · Daniel B. Sinars · Roger A. Vesey

Abstract and summary · read the original at the source · none found

In one page

Adam Sefkow and his colleagues at Sandia and Livermore designed, on the computer, the first fusion shots of magnetized liner inertial fusion, and then Sandia fired them. The idea is simple to picture: a metal tube about a centimetre tall, filled with deuterium gas, sitting inside a magnetic field. A pulse of nineteen million amps from the Z machine crushes the tube inward in tens of nanoseconds, a laser fires down a hole in the top to pre-warm the gas, and the magnetic field, squeezed along with the fuel, keeps the heat from leaking sideways and holds the fusion alpha particles inside to warm the plasma further. What is new here is that the calculation includes all of it at once — the laser heating, the electrodes, the fuel escaping out of the ends. The team reports what the machine should produce now, what an upgraded Z could produce, and what a seventy-million-amp successor could produce with frozen fuel.

Why it matters hereChapter 12 needs a worked example of the move that makes compact fusion plausible — trading brute compression for magnetisation, so that the same result is reached at a fifth of the implosion speed and a hundredth of the stagnation pressure — and this is that example, with the numbers and the machine both named. For chapter 9 it is a study of a magnetically self-insulated plasma column: the seed field is compressed by a factor of a thousand, to tens of megagauss, and that field, not density, is what confines the alphas.

What it claims

01The magnetized liner inertial fusion target is a solid cylindrical beryllium or aluminium liner about one centimetre tall, holding a gas fuel fill of one to five milligrams per cubic centimetre; an external coil pre-seeds an axial magnetic field of five to a hundred tesla, the accelerator’s megaampere axial current drives the implosion through the Lorentz force on a tens-of-nanoseconds timescale, and a laser delivering two to twenty-five kilojoules through an entrance hole in the top preheats the fuel to ion temperatures of fifty to five hundred electronvolts.Section I, Introduction; Figure 1, schematic of the MagLIF concept
Published and peer-reviewed
02Magnetising the fuel replaces the requirement on areal density with a requirement on the compressed field times the radius, so that fusion-relevant ion temperatures above four kilo-electronvolts are reached at convergence ratios of twenty to thirty and implosion velocities near a hundred kilometres per second — against convergence above thirty and velocities above three hundred kilometres per second in traditional inertial confinement fusion — and the stagnation pressure needed falls from hundreds of gigabars to a few.Section I, Introduction
Published and peer-reviewed
03The initial axial field is flux-compressed to five to ten kilotesla at stagnation, that is fifty to a hundred megagauss, which magnetises the fusion alpha particles so that they self-heat the plasma; magnetic Reynolds numbers run from a few thousand to ten thousand and the Hall parameter can exceed a few hundred at its peak.Section I, Introduction
Published and peer-reviewed
04Integrated HYDRA simulations predict deuterium-deuterium neutron yields of two to eight times ten to the thirteenth on Z with presently available capabilities; the first integrated experiments produced yields of half to two times ten to the twelfth at the expected three kilo-electronvolt temperature, with a convergence ratio near forty, low mix, isotropic yields and spectra, and a primary-to-secondary neutron yield ratio of forty to eighty that indicates the fuel was magnetised.Section VI, Summary and Discussion; Table II, present-on-Z column
Published and peer-reviewed
05Laser timing has an optimum, found by repeating the design simulation with the preheat trigger moved forty nanoseconds either way in five-nanosecond steps: the best moment is when the inner liner boundary begins to implode, because preheating earlier increases end losses, plasma cooling and the potential for mix, while preheating later gives less effective compression. The Z-Beamlet timing jitter of about four and a half nanoseconds keeps the shot near peak potential yield.Section IV C, Laser timing and coupling efficiency; Figure 11
Published and peer-reviewed
06Scaling the design forward, an upgraded Z at twenty-four megaamperes with six kilojoules of preheat and a forty tesla seed field simulates to a deuterium-tritium yield of three times ten to the sixteenth and a fusion energy of about eighty-five kilojoules; on a new seventy-megaampere accelerator with twenty-five kilojoules of preheat and cryogenic solid deuterium-tritium fuel, one-dimensional simulations reach ten gigajoules per centimetre with a target gain of one thousand.Section V A and V B, Design of future experiments; Table II, upgrades and new-machine columns; Figure 14
Designed, not yet built

Read it · abstract

Abstract

The magnetized liner inertial fusion concept has been presented as a path toward obtaining substantial thermonuclear fusion yields using the Z accelerator [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)]. We present the first integrated magnetohydrodynamic simulations of the inertial fusion targets, which self-consistently include laser preheating of the fuel, the presence of electrodes, and end loss effects. These numerical simulations provided the design for the first thermonuclear fusion neutron-producing experiments on Z using capabilities that presently exist: peak currents of 18–20 MA, pre-seeded axial magnetic fields of 10 T, laser preheat energies of about 2 kJ delivered in 2 ns, DD fuel, and an aspect ratio 6 solid Be liner imploded to 70 km/s. Specific design details and observables for both near-term and future experiments are discussed, including sensitivity to laser timing and absorbed preheat energy. The initial experiments measured stagnation radii of less than 75 μm, temperatures around 3 keV, and isotropic neutron yields up to 2 × 10¹² DD neutrons, with inferred alpha-particle magnetization parameters — the ratio of the stagnation radius to the alpha Larmor radius — around 1.7 [M. R. Gomez et al., Phys. Rev. Lett. (submitted)].

The way in

https://doi.org/10.1063/1.4890298LICENCE CHECK, 2026-09-08, and a registry correction. The skeleton and the fetched record both carried Creative Commons Attribution 3.0, taken from the Crossref deposit and repeated by Unpaywall, OpenAlex and Semantic Scholar. That label does not survive checking. The version of record, Physics of Plasmas volume 21, article 072711, published online 24 July 2014, carries the copyright line ‘© 2014 AIP Publishing LLC’ on its first page and repeats it in the page furniture, and the phrase Creative Commons appears nowhere in the eighteen pages of the article; the publisher’s own article page, read from an archived capture, carries no Creative Commons statement either, only an Open badge and a CHORUS link, which is public-access reading, not a Creative Commons grant. The deposit is a journal-level default: the same Crossref licence block, Creative Commons Attribution 3.0 for the version of record, is attached to Physics of Plasmas 17, 056303 (2010), the subscription Slutz paper this article cites in its own first sentence. So this sheet carries the summary, the claims and the published abstract, and sends the reader to the source. TEXT. The full text was read for this sheet, from the publisher PDF as archived by the Internet Archive from aip.scitation.org, and every claim below is located against it by section, table and figure number; the abstract reproduced here is the published one from that same PDF, with its subscripts spelled out and its exponents restored. A Sandia conference presentation of the same design work, SAND2013-10007C, is openly available from the Office of Scientific and Technical Information as record 1120871, and gives the slides but not the text. On this site, the experiment this design produced is at [/library/stm-d11937cf2a](/library/stm-d11937cf2a), the high-gain projection it builds toward is at [/library/stm-b7ffaf8ee4](/library/stm-b7ffaf8ee4), and the sheared-flow-stabilized approach to the Z-pinch is at [/library/stm-d90424cb8a](/library/stm-d90424cb8a).

How to cite it

Adam B. Sefkow, Stephen A. Slutz, Joseph M. Koning, Michael M. Marinak, Kyle J. Peterson, Daniel B. Sinars, Roger A. Vesey (2014) Design of magnetized liner inertial fusion experiments using the Z facility. doi:10.1063/1.4890298

Where it sits in the curriculum

Plasmoids, charge clusters and the orbs Lattice confinement fusion